Setup for evaluation of heat transfer coefficient of refrigerant blends

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F16%3A00306439" target="_blank" >RIV/68407700:21220/16:00306439 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Setup for evaluation of heat transfer coefficient of refrigerant blends

Original language description

We have designed and constructed an experimental setup for evaluation of the flow boiling heat transfer coefficient (HTC) in refrigerant mixtures. The setup was primarily used to evaluate heat transfer coefficient and also related behaviour such as the pressure drop and mass flow patterns of binary blends consisting of R-218 (C3F8) and up to 25% molar of R-116 (C2F6). These blends are foreseen as a potential replacement for pure R-218 refrigerant which is currently being used in the evaporative cooling system of the ATLAS inner detector at CERN. Owener: CTU Prague, Department of Physics and ID community of the ATLAS experiment.

Czech name

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Czech description

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Type

G_funk - Functional sample

CEP classification

BJ - Thermodynamics

OECD FORD branch

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Project

<a href="/en/project/LM2015058" target="_blank" >LM2015058: Research Infrastructure for Experiments at CERN</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Internal product ID

HTC_2016_001

Numerical identification

2016001

Technical parameters

The setup was design to simulate the conditions of the ATLAS Inner detector cooling structures. A one-meter long horizontal thin copper-nickel tube with 4 mm internal diameter is used as an evaporator. Direct electric heating (up to 140 W) is applied to the tube in order to simulate the heat load of the silicon particle detectors. More than twenty calibrated Pt1000 sensors are installed along the tube, both on the top and on the bottom of the tube. Such arrangement is necessary for a low mass-flow measurement with stratified flows inside the evaporator where the boiling liquid tends to pool at the bottom of the cooling tube. Two capillaries provide mass flows of 1-3 g/s equivalent to the ATLAS inner detector cooling. The most unique component of the test loop is an instrument for precise analysis of the blends composition using speed-of-sound data monitored in flowing refrigerant mixture. Dedicated panels running in WinCC SCADA were prepared to visualize, store and archive the measured data.

Economical parameters

Estimated cost of the experimental setup and developed software is around 350 thousand of CZK. Our setup was used to evaluate performance of refrigerant blends that are proposed to replace current pure refrigerant in the ATLAS inner detector cooling. The blends would allow for lower evaporation temperature without any major modifications of the cooling system that is currently in place. The cost savings related to the use of such mixtures are therefore obvious. Using the blends that would be the same price as current pure refrigerant and can save hundreds of thousands of euros that would be needed to replace at least some of the suction lines to eliminate pressure drops and enable lower evaporation pressures. The blends would be also beneficial for the new cooling system called “Thermosiphon” that is currently being commissioned. They could enable substantial cost saving in maintenance and running costs by allowing the Thermosiphon to operate with higher suction pressure at the same evaporation temperature.

Application category by cost

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Owner IČO

68407700

Owner name

ústav fyziky

Owner country

CZ - CZECH REPUBLIC

Usage type

N - Využití výsledku jiným subjektem je možné bez nabytí licence (výsledek není licencován)

Licence fee requirement

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Web page

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